Partially crystallizing ceramic enamel composition containing bismuth silicate, and use thereof

Abstract

A ceramic enamel composition consists of an oxide frit, a bismuth silicate seed material, a pigment, and a vehicle. A preferred bismuth silicate seed material is selected from crystalline Bi 12 SiO 20 , Bi 4 (SiO 4 ) 3 , and Bi 2 SiO 5 , and mixtures thereof. Upon firing a glass substrate coated with the enamel, components of the enamel adhere to the substrate. The glass can be formed with a die to a desired shape with reduced sticking of the coated region to the die. The ceramic enamel is particularly useful in providing a colored border around automotive glass, which enhances appearance and reduces degradation of adhesives by ultraviolet radiation.

What is claimed is:  
     
       1. A ceramic enamel composition comprising 20-80% by weight of an oxide frit, an amount of a bismuth silicate seed material sufficient to cause nucleation and growth of crystals leading to increased refractoriness and devitrification in the composition upon firing, 10-40% by weight of a pigment, and 10-40% by weight of an organic vehicle. 
     
     
       2. The composition of claim  1 , wherein the oxide frit contains at least one of bismuth oxide and zinc oxide. 
     
     
       3. The composition of claim  1 , wherein the bismuth silicate seed material is provided as seed crystals in the composition. 
     
     
       4. The composition of claim  3 , wherein the bismuth silicate seed crystals contain at least one phase selected from the group consisting of Bi 12 SiO 20 , Bi 4 (SiO 4 ) 3 , and Bi 2 SiO 5 . 
     
     
       5. The composition of claim  1 , wherein the composition further contains a material selected from the group consisting of alumina-silicate compounds, calcium silicate compounds, boro-alumina-silicate compounds, soda-calcia-alumina-silicate compounds, feldspar compounds, titania, and mixtures thereof. 
     
     
       6. The composition of claim  1 , further comprising a silver bleed-through resistant material containing iron, silicon, or zinc. 
     
     
       7. A method of forming a glass substrate with an adherent ceramic enamel coating comprising applying a ceramic enamel composition as in claim  1  to the glass substrate, and heating the coated glass substrate to an elevated temperature to fuse components of the ceramic enamel composition to the glass substrate. 
     
     
       8. The method of claim  7 , wherein the ceramic enamel composition is applied to at least a portion of the periphery of the glass substrate. 
     
     
       9. The method of claim  7 , further comprising subjecting the heated glass to a forming pressure with a die, and separating the formed glass from the die. 
     
     
       10. A method of preparing a ceramic enamel composition comprising combining 20-80% by weight of an oxide frit, an amount of a bismuth silicate seed material sufficient to cause nucleation and growth of crystals leading to increased refractoriness and devitrification in the composition upon firing, 10-40% by weight of a pigment, and 10-40% by weight of an organic vehicle. 
     
     
       11. A glass substrate having a ceramic enamel coating adherent thereto, said coating being obtained by applying to at least a portion of a glass substrate a ceramic enamel composition comprising 20 to 80% by weight of an oxide frit, an amount of a crystalline bismuth silicate seed material sufficient to cause nucleation and growth of crystals leading to increased refractoriness and devitrification in the composition upon firing, 10 to 40% by weight of a pigment and 10 to 40% by weight of an organic vehicle and heating the coated glass substrate to an elevated temperature to fuse components of the ceramic enamel composition to the glass substrate. 
     
     
       12. A glass substrate according to claim  11  wherein the glass substrate is automotive glass. 
     
     
       13. A glass substrate according to claim  12  wherein the enamel composition is applied to the periphery of the glass substrate. 
     
     
       14. A glass substrate according to claim  11  wherein, in the ceramic enamel composition, the oxide frit contains at least one member selected from the group consisting of bismuth oxide and zinc oxide. 
     
     
       15. A glass substrate according to claim  11  wherein, in the ceramic enamel composition, the crystalline bismuth silicate seed material contains at least one phase selected from the group consisting of Bi 12 SiO 20 , Bi 4 (SiO 4 ) 3  and Bi 2 SiO 5 . 
     
     
       16. A glass substrate according to claim  11  wherein the ceramic enamel composition further contains a material selected from the group consisting of alumina-silicate compounds, calcium silicate compounds, boro-alumina-silicate compounds, soda-calcia-alumina-silicate compounds, feldspar compounds, titania, and mixtures thereof. 
     
     
       17. A glass substrate according to claim  11  wherein the ceramic enamel composition further comprises a silver bleed-through resistant material containing iron, silicon, or zinc.